Dennis Rodman sang “Happy Birthday” Wednesday to North Korean leader Kim Jong Un before leading a group of former NBA basketball players onto the court as part of Rodman’s controversial “basketball diplomacy” program.

Rodman called Kim his “best friend” as the leader watched from the stands with his family, the Associated Press reports. About 14,000 people filled Pyongyang stadium to watch the game between former American basketball stars and the North Korean team.

The American team, mostly in their late 40s, included former stars like Cliff Robinson, Kenny Anderson, and Charles D. Smith. The Americans played against the North Korean team for the first half of the game, and then mixed up the teams for the second half.

The other American players did not join Rodman in singing for the North Korean leader, and former Knicks forward Charles D. Smith told the Associated Press he had advised Rodman against it. “We always tell Dennis that he can’t sing. He is tone deaf,” Smith said. “He did it alone.”

Calling the leader his “best friend” is a new development for the controversial relationship between the eccentric basketball star and Kim Jong Un, especially since the leader rarely meets with foreigners. Members of Congress and the NBA have denounced the friendship as dangerous and naive, and Rodman has come under intense criticism from human rights groups for not using his influence to help free American hostage Kenneth Bae, who is poor health.